CVE-2021-3618

{"dataType": "CVE_RECORD", "dataVersion": "5.1", "cveMetadata": {"state": "PUBLISHED", "cveId": "CVE-2021-3618", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "assignerShortName": "redhat", "dateUpdated": "2024-08-03T17:01:07.459Z", "dateReserved": "2021-06-24T00:00:00.000Z", "datePublished": "2022-03-23T00:00:00.000Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2022-11-23T00:00:00.000Z"}, "descriptions": [{"lang": "en", "value": "ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer."}], "affected": [{"vendor": "n/a", "product": "ALPACA", "versions": [{"version": "vsftpd 3.0.4, nginx 1.21.0, sendmail 8.17", "status": "affected"}]}], "references": [{"url": "https://bugzilla.redhat.com/show_bug.cgi?id=1975623"}, {"url": "https://alpaca-attack.com/"}, {"name": "[debian-lts-announce] 20221122 [SECURITY] [DLA 3203-1] nginx security update", "tags": ["mailing-list"], "url": "https://lists.debian.org/debian-lts-announce/2022/11/msg00031.html"}], "problemTypes": [{"descriptions": [{"type": "CWE", "lang": "en", "description": "CWE-295", "cweId": "CWE-295"}]}]}, "adp": [{"providerMetadata": {"orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-03T17:01:07.459Z"}, "title": "CVE Program Container", "references": [{"url": "https://bugzilla.redhat.com/show_bug.cgi?id=1975623", "tags": ["x_transferred"]}, {"url": "https://alpaca-attack.com/", "tags": ["x_transferred"]}, {"name": "[debian-lts-announce] 20221122 [SECURITY] [DLA 3203-1] nginx security update", "tags": ["mailing-list", "x_transferred"], "url": "https://lists.debian.org/debian-lts-announce/2022/11/msg00031.html"}]}]}}

{}

{"affected": [{"affectedData": [{"product": "ALPACA", "vendor": "n/a", "versions": [{"status": "affected", "version": "vsftpd 3.0.4, nginx 1.21.0, sendmail 8.17"}]}], "source": "secalert@redhat.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:f5:nginx:*:*:*:*:*:*:*:*", "matchCriteriaId": "777D8DB3-65CF-4A12-BCCE-30849CE07762", "versionEndExcluding": "1.21.0", "vulnerable": true}], "negate": false, "operator": "OR"}]}, {"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:sendmail:sendmail:*:*:*:*:*:*:*:*", "matchCriteriaId": "2E5DF525-823F-49D0-BDD2-6BCE5EE0F66B", "versionEndExcluding": "8.17", "vulnerable": true}], "negate": false, "operator": "OR"}]}, {"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:vsftpd_project:vsftpd:*:*:*:*:*:*:*:*", "matchCriteriaId": "CA84E5A7-7557-4805-902B-E8069F5F4091", "versionEndExcluding": "3.0.4", "vulnerable": true}], "negate": false, "operator": "OR"}]}, {"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*", "matchCriteriaId": "E460AA51-FCDA-46B9-AE97-E6676AA5E194", "vulnerable": true}, {"criteria": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*", "matchCriteriaId": "A930E247-0B43-43CB-98FF-6CE7B8189835", "vulnerable": true}, {"criteria": "cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*", "matchCriteriaId": "80E516C0-98A4-4ADE-B69F-66A772E2BAAA", "vulnerable": true}], "negate": false, "operator": "OR"}]}, {"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*", "matchCriteriaId": "07B237A9-69A3-4A9C-9DA0-4E06BD37AE73", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer."}, {"lang": "es", "value": "ALPACA es un ataque de confusi\u00f3n de contenido de protocolo de capa de aplicaci\u00f3n, que explota servidores TLS que implementan diferentes protocolos pero que usan certificados compatibles, como certificados multidominio o comod\u00edn. Un atacante de tipo MiTM que tenga acceso al tr\u00e1fico de la v\u00edctima en la capa TCP/IP puede redirigir el tr\u00e1fico de un subdominio a otro, resultando en a una sesi\u00f3n TLS v\u00e1lida. Esto rompe la autenticaci\u00f3n de TLS y pueden ser posibles los ataques entre protocolos donde el comportamiento de un servicio de protocolo puede comprometer al otro en la capa de aplicaci\u00f3n"}], "id": "CVE-2021-3618", "lastModified": "2026-06-17T04:05:27.083", "metrics": {"cvssMetricV2": [{"acInsufInfo": false, "baseSeverity": "MEDIUM", "cvssData": {"accessComplexity": "MEDIUM", "accessVector": "NETWORK", "authentication": "NONE", "availabilityImpact": "NONE", "baseScore": 5.8, "confidentialityImpact": "PARTIAL", "integrityImpact": "PARTIAL", "vectorString": "AV:N/AC:M/Au:N/C:P/I:P/A:N", "version": "2.0"}, "exploitabilityScore": 8.6, "impactScore": 4.9, "obtainAllPrivilege": false, "obtainOtherPrivilege": false, "obtainUserPrivilege": false, "source": "nvd@nist.gov", "type": "Primary", "userInteractionRequired": false}], "cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 7.4, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 5.2, "source": "nvd@nist.gov", "type": "Primary"}]}, "published": "2022-03-23T20:15:09.833", "references": [{"source": "secalert@redhat.com", "tags": ["Third Party Advisory"], "url": "https://alpaca-attack.com/"}, {"source": "secalert@redhat.com", "tags": ["Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1975623"}, {"source": "secalert@redhat.com", "tags": ["Mailing List", "Third Party Advisory"], "url": "https://lists.debian.org/debian-lts-announce/2022/11/msg00031.html"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Third Party Advisory"], "url": "https://alpaca-attack.com/"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Issue Tracking", "Patch", "Third Party Advisory"], "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1975623"}, {"source": "af854a3a-2127-422b-91ae-364da2661108", "tags": ["Mailing List", "Third Party Advisory"], "url": "https://lists.debian.org/debian-lts-announce/2022/11/msg00031.html"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Modified", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-295"}], "source": "secalert@redhat.com", "type": "Secondary"}, {"description": [{"lang": "en", "value": "CWE-295"}], "source": "nvd@nist.gov", "type": "Secondary"}]}

{"bugzilla": {"description": "ALPACA: Application Layer Protocol Confusion - Analyzing and Mitigating Cracks in TLS Authentication", "id": "1975623", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=1975623"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.4", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "status": "draft"}, "cwe": "CWE-295", "details": ["ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer.", "ALPACA is an application layer protocol content confusion attack, exploiting TLS servers implementing different protocols but using compatible certificates, such as multi-domain or wildcard certificates. A MiTM attacker having access to victim's traffic at the TCP/IP layer can redirect traffic from one subdomain to another, resulting in a valid TLS session. This breaks the authentication of TLS and cross-protocol attacks may be possible where the behavior of one protocol service may compromise the other at the application layer."], "mitigation": {"lang": "en:us", "value": "1. Avoid wildcard certificates or multi-domain certificates if you are hosting several TLS-enabled application servers on the same hostname.\n2. Two extensions in TLS can provide some protection to the application layer protocol: SNI and ALPN."}, "name": "CVE-2021-3618", "package_state": [{"cpe": "cpe:/a:redhat:ansible_automation_platform", "fix_state": "Not affected", "package_name": "Ansible", "product_name": "Red Hat Ansible Automation Platform 1.2"}, {"cpe": "cpe:/a:redhat:ansible_tower:3", "fix_state": "Out of support scope", "package_name": "nginx", "product_name": "Red Hat Ansible Tower 3"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "httpd", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "postfix", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "impact": "low", "package_name": "sendmail", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "vsftpd", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "httpd", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "postfix", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "impact": "low", "package_name": "sendmail", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Out of support scope", "package_name": "vsftpd", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "httpd:2.4/httpd", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Will not fix", "package_name": "nginx:1.16/nginx", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Will not fix", "package_name": "nginx:1.18/nginx", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Will not fix", "package_name": "nginx:1.20/nginx", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "postfix", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "impact": "low", "package_name": "sendmail", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Will not fix", "package_name": "vsftpd", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "dovecot", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "httpd", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "nginx", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "postfix", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "impact": "low", "package_name": "sendmail", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "vsftpd", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:rhel_software_collections:3", "fix_state": "Not affected", "package_name": "httpd24-httpd", "product_name": "Red Hat Software Collections"}, {"cpe": "cpe:/a:redhat:rhel_software_collections:3", "fix_state": "Will not fix", "package_name": "rh-nginx116-nginx", "product_name": "Red Hat Software Collections"}, {"cpe": "cpe:/a:redhat:rhel_software_collections:3", "fix_state": "Will not fix", "package_name": "rh-nginx118-nginx", "product_name": "Red Hat Software Collections"}], "public_date": "2021-06-09T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2021-3618\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-3618\nhttps://alpaca-attack.com/"], "statement": "Conditions required for the attack to work:\n1. As per mentioned above you need a MiTM atack who can divert victim's traffic at the TCP/IP layer and therefore the only plausible attack model is on the local network.\n2. If you are hosting several TLS-enabled application servers on the same hostname, or if you use multi-domain certificates, or if you use wild-card certificates, you may be vulnerable to the general confusion attack.", "threat_severity": "Moderate"}

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